[squarecat]

Hence the emergence of such legislation as: https://en.wikipedia.org/wiki/CAN-SPAM_Act_of_2003

Of which the efficacy is certainly arguable, since a truly reputable firm might seek to provide such a mechanism in an easy-to-use manner. Whereas a shady operation would, and do, ignore the directive anyhow.

[StavrosK]

Sure, but by making it hard for legitimate companies to spam you, we get a much clearer separation of spam from ham. You don't have to know who all the bad guys are, it's enough to know who all the good guys are.

These days, messages in my inbox fall into two categories: Messages with an "unsubscribe" link, or spam.

This didn't use to happen in the olden days.